Steering and suspension mechanism for driven wheels



Sept. 27, 1960 c. HILL 2,954,089 STEERING AND SUSPENSION MECHANISM FORDRIVEN WHEELS Filed Aug. 16. 1955 3 Sheets-Sheet.- 1

' Sept. 27, 1960 Filed Aug. 16, 1955 c. HILL 2,954,089

STEERING AND SUSPENSION MECHANISM FOR DRIVEN WHEELS 5 SheetsSheet 2 Spt.27, 1960 c. HILL 2,954,089

STEERING AND SUSPENSION MECHANISM FOR DRIVEN WHEELS Filed Aug. 16, 19553 Sheets-Sheet 3 43 P J .50 L 59a 62! Jifl T- INV'ENTQR. 6 /622401? ZQZZ BY w,%m

STEERING AND SUSPENION MECHANISM FOR DRIVEN WHEELS Claude Hill,Kenilworth, England, assignor to Harry Ferguson Research Limited,Stow-on-thc -Wold, England Filed Aug. 16, 1955, Ser. No. 528,732

Claims priority, application Great Britain Aug. 25, 1954 2 claims. Cl.180-42) The present invention relates to steering mechanisms for. motorvehicles andmore particularly to rack-andpinion type steering mechanismsof the general type disclosed in my co-pending application for U. S.patent Serial No. 332,793, filed January 23, 1953, now U.S. Patent No.2,775,307, and assigned to the same assignee as the present invention,wherein the front wheels are employed as driving wheels as well as forsteering. in such arrangements, the front wheels are associated withseparate power driven half-axle assemblies universally pivoted to thevehicle chassis for up-and-down suspension movement.

In motor vehicles of this type having the power unit forwardly disposedon the chassis, such as disclosed in the above mentioned US Patent No.2,775,307, the steering mechanism is conventionally located to the rearof the power unit and usually above the change speed transmissiongearing. However, where for various reasons it isdesirable to shift thepower unit somewhat rearwardly on the chassis, a difficulty isencountered in lo cating the steering mechanism so that it is mounted onthe chassis and yet is close enough to the front wheels to give smoothsteering action.

Accordingly, it is a general object of the present invention to providean improved steering mechanism for use ina vehicle having independentlysuspended front-wheels, which mechanism is adapted for location forwardof'the front wheel half-axle assemblies whereby steering may beetfectedwithout interference with the vehicle engine and transmission gearing.

It is an allied object of the present invention to provide a steeringmechanism of such type whereby relative up-and-down road motion betweenthe vehicle chassis and the independently suspended front half-axleassemblies will not cause any inadvertent steering action so as to,turnthe road wheels when such turning is not desired.

It is another object of the invention to provide a steeringmechanism ofthe above type wherein rack-and-pinion gearing is employed fortransmitting steering motion from the vehicle steering column to thefront road wheels through a pair of push-pull links connectedwithappropriate steering knuckle arms and located forwardly of the fronthalf-axle assemblies.

It is an associated object of the invention to provide such a steeringmechanism wherein the rack-and-pinion gearing is remotely located withrespect to the push-pull links and is operatively associated therewithby means of a connector member aflixed to the push-pull links onopposite sidesof the vehicle and connected to the rack so as to transmitthe movements thereof through the links and to the steering arms. It isa further allied object to provide such a rack-and-pinion steeringmechanism wherein the connector member is completely supported suitablebearings carried by the chassis so that the rack is subjected to purelyaxial thrust and is safeguarded against oblique reactive forces from thepush-pull links.

:Finally, it is an object of the present invention to provide a steeringmechanism for use with independently suspended front wheel, drivevehicles, which mechanism is economically manufactured, simple toassemble and repair, and requires a minimum of care and maintenance;

Other objects and advantages of the invention will become apparent uponreading the attached detailed description, and upon reference to thedrawings, wherein:

Figure 1 is a plan view, partly in section, of the front wheel half-axleassembly at the right hand side of a motor vehicle.

Fig. 2 is a vertical sectional view taken along the line 2- 2 in Fig. 1.

Fig. 3 is a vertical sectional View taken along the line 33 in Fig. 1.

Fig. 4 is a transverse vertical section taken at the axis of one of theaxles which transmit the drive to the front road wheels, as viewed fromthe front of the vehicle.

Fig. 5 is a diagrammatic view, showing in outline form the components ofthesteering mechanism and suspension means as illustrated in Fig. 4, andshowing the approximate parallelogramic arrangement of pivotalconnections therebetw'een.

While the invention has been described in connection withv a preferredembodiment, it will be understood that it is not intended to limit theinvention thereto but it is intended to cover all modifications andalternative constructions falling within the spirit and scope of theappended claims.

Turning now to the drawings, an exemplary vehicle is here illustrated.Since the front suspension is identical for each front wheel, thefollowing description of one side will sufiice for both. At the outsetit should be noted that the present front suspension is of the genusdisclosed and claimed in my Patent No. 2,775,307 to which reference maybe had for details of the suspension employed herein.

The vehicle includes a central frame or chassis (not shown) to which areattached a pair of castings 10 (only one shown) alfixed to thefore-and-aft main chassis members. The vehicle power unit (also notshown) is supported by the castings 19 and the entire chassis issuspended in relation to the front wheel half-axle as semblies 12, aswill be discussed. The illustrative vehicle is one in which the engineextends above the front axle assemblies 12 in such a manner as toprohibit location of the vehicle steering mechanism in the conventionalposition rearward of these assemblies. For reference purposes, thecentral vertical plane of the engine is indicated by the line 14 and thecentral fore-and-aft plane of the vehicle is indicated by the line '16.

Referring now particularly to Fig. 1, itwill be observed that the outputshaft 18 of the power unit (not shown) carries an endflange 20 adaptedto receive a bolted annular disc 22 to form a disc brake of any suitableknown construction, the other parts of which are not shown. The samebolts which secure the brake disc 22 to thefiange 24 may extend into aneck 24 provided in each of the castings 10 to mount a deformable,resilient element preferably a rubber disc 26 and a spider 28 rigidlysecured to the inner end of the front half-axle or shaft 3t). Thespider, in turn, carries bolts engaged in the remaining holes of therubber disc 26. Such a resilie nt universal joint has been described inthe co-pending application of Anthony Rolt et al. for US. patent, SerialNo. 395,978, filed December 3, 1953 of common ownership with the presentapplication, and reference may be made to Patent No. 2,796,943 nowissued from that application for further details of the jointconstruction.

Attention may now be given briefly to the relation between the vehiclechassis and the vertically swingable half-axle assembly 12. It will beseen that the half-axle is rotatively disposed within a half-axlehousing 3011 1nd the outer portion of this axle is journaled in aselfiligning type bearing 31 (Fig. 2 carried by .the inner end )f aninner ball joint component 32 which, by cooperatng with an outer balljoint component 34 forms a front Wheel universal joint 36.

The power driven wheel and axle assembly here em- )loyed issubstantially the same as that disclosed in my :o-pending applicationfor US. patent, Serial No. 499,713, iled April 6, 1955 (now abandoned),and reference may Je made to that application for details of thisassembly. Buffice it to say that the front road wheel 38 is mounted lpona stub-axle assembly 40 (Fig. 4) which includes a ion-rotatable sleeve34a for mounting the wheel, the :leeve being integrally formed with theouter ball joint :omponent 34 of the universal joint 36. A suitable stublxle bearing 35 is included with the assembly 40 for ournaling the wheelhub 42 on the non-rotatable sleeve. Thus, a live connection isestablished between the output ;haft 18 of the power unit and the wheelhub 42, pernitting the entire wheel and half-axle to swing verticallywith respect to the vehicle chassis, and the wheel to swing iniversallyabout the end of the half-axle for steering purposes.

Spring means for the front suspension arrangement is arovided byvertically disposed coil spring 46 interposed )etween an upstanding boss46a (Fig. 4) on the half-axle and a downwardly extending boss 4612 onthe underside )f the chassis.

The control linkage for the half-axle suspension is substantially thesame as that shown in the above referred US. Patent No. 2,796,943. Forpurposes of disclosing ;he present invention it is suflicient to statethat the :ontrol linkage includes a lower system of duplex links 48extending upwardly and inwardly from a pivot conlection 48a to the lowerend of the kingpin assembly 47 which is carried beneath the outer balljoint component 34. The duplex links 48 are pivotally connected at theirnedial portions with a vertically disposed shackle 50 which is pivotedat 54 to the underside of the half-axle :asing 30a and carries a singletransverse pivot bolt 500. Also connected to the shackle 50 is a link 52which ex- :ends inwardly and downwardly from the shackle to a .ow levelpivotal connection 52a with the vehicle chassis. Thus, the shackle bolt50a serves as the pivotal connec- ;ion for the links 48 and the link 52.

The control linkage is completed in the mechanism 1ewly described hereinby the provision of a chassis supporting yoke 56 of wishbone typeinterposed between the :asting 10 and the shackle 59. From the drawingsit will be seen that the yoke 56 comprises a body portion 57, whichsurrounds and is welded to the half-axle casing 50a adjacent the shackle50, and a pair of oppositely iisposed limbs 58 which are connected atspaced points :0 the casting 10 by a pair of pivot bolts 59. Thus, the;winging yoke 56 forms the component of the control linkage between thevehicle chassis and the road-wheel ialf-axle assembly 12 and the alignedfore-and-aft pivotal :onnections at 59 are seen to be spaced sidewisefrom :he central fore-and-aft plane 16 of the vehicle.

Thus, it is apparent that the suspension means for each of the powerdriven front half-axle assemblies 12 in- :ludes a swinging link in theform of the yoke 56,- the limbs 58 of which are pivotally connected asat 59 to the vehicle chassis so that the link can swing up and downibOllt the fore-and-aft axis of the pivotal connections. The yoke body57 is disposed outwardly with respect to :he chassis and attached to anon-rotary axle component (the half-axle casing 30a) which latter is inproximity :o the road wheel 38.

Steering of the front wheels is accomplished by pivoting the universaljoint 36 about the axis 47a defined by the kingpin assembly 47 (Fig. 4).A steering knuckle arm 60 (Fig. 1) is bolted to a pad 62 which isintegral with the outer ball joint component 34, and the arm 60 isconnected at its front end to a transverse push-pull link or tie rod 66by means of a ball and socket joint 64.

In accordance with the present invention, a steering mechanism 68 isprovided including a rack-and-pinion assembly located forward of thefront half-axle assemblies 12 and yet so arranged with respect to thefront suspension control linkage that there is no inadvertent steeringmotion imparted to the vehicle due to rise and fall of the chassis withrespect to the road wheels when the vehicle passes over bumps andobstructions in the road. In this instance, the steering mechanism 68includes a steering column 79 (Fig. 2) which is offset to one side ofthe associated casting 10 because of the location of the vehicle motor.The column 70 extends upwardly into the drivers compartment of thevehicle and comprises an upper tubular member 70a and an aligned lowershaft 79b jointed thereto bymeans of 'a universal joint 72. The mainsupport for the steering column 70 is provided by a hollow T-shaped rackcasing 74 in which the steering shaft 70b is journaled and which has atransverse portion 74a rigidly attached to the casting 10 by means of atubular arm 76. As will be observed the tubular arm has a portion 76awhich extends slightly inwardly through a suitable opening in theassociated casting Ill.

Splined to the extreme lower end of the steering shaft 70b is a pinion78 which is engageable with a rack gear 80 arranged transversely of thevehicle and movable through the transverse portion 74a of the rackcasing. To prevent slackness which would otherwise occur with wear ofthe rack-and-pinion teeth, the rack 80 is held in continuous mesh withthe pinion 78 by a presser 82 mounted in an upper projection of the rackcasing 74. The presser 82 is maintained in sliding contact with thesmooth upper surface of the rack 80 by a compression spring 84interposed between the top of the presser 82 and a cap 74b which sealsthe upper projection of the rack casing 74. The rack casing 74 alsoforms an oil bath for the parts within it, being provided with suitableoil seals (not shown) at its various openings.

As shown, the outer end of the rack 80 is fitted with a bellows typeseal 86 which extends from the rack casing '74 and totally encloses thelength of rack projecting outwardly from the casing. The bellows 86 issupported by a pair of spaced collars 88, 90, located respectively onthe end of the rack 80 and on the outer end of the transverse casingportion 74a.

Because of the spacing of the steering column 70 sidewise of the centralcasting 10, it is obvious that it would be manifestly impossible todirectly connect the pushpull link 66 to the ends of the rack 80.Accordingly, means are provided for operatively connecting theseelements, such means including a transverse connector member or bar 92symmetrically arranged as a rigid component of the transversely movablerack-and-pinion steering unit. As will be seen from Fig. 1, the innerend of the rack 80 extends through the tubular arm 76 and into anoval-section casing 94 which bridges the spaced castings 10 and therebyserves not only as an enclosure for the rack unit but also as a strongcross brace for the front end of the chassis.

The connector 92 is disposed substantially Within the bridging casing 94and comprises an elongated bar having a circular cross-section. Theconnector is arranged somewhat beneath the rack 80 and is axiallyslidable near each of its ends through a self-aligning andselflubricating bearing 96 disposed in an appropriate recess providedwithin each casting Ml. A heavy bracket 98 secures the middle of theconnector bar 92 to the inner end of the rack 80 (Figs. 1 and 3). Thus,it is seen that the assembly including the rack 80, the transverseconnector 92, and the bracket 98 forms a rigid unit which is movableto-and-fro crosswise of the vehicle. As shown in Fig. 1, the middle ofthe transverse connector 92 coincides in the mid-portion of thesteeringmechanism withthe central fore-and-aftplane16 of the vehicle.

Each outwardly projecting end of the connector-32 is jointed with theadjacent end of the associated, push pull 66,by iheans of a ball andsocket joint 10;). Again, a bellows type seal 102 is employed to housethe outwardly extending end of the connector 92 and the joint 100. Thebellows 102 extends between supporting colla'rs 104, 10 6 providedrespectively on the push-pull link 66 and thecasting 10 adjacent theconnector 92'.

Summarizing, then, it will be observed that the steering mechanismcomprises steering arm'sltl on the front road wheel axle assemblies 12,a rack 89 mounted so as to be movable transversely of the vehicle, apair of transverse push-pull links 66 and a connector 92 formingconnections between the rack and steering arms, each link having pivotalconnections at both ends, and a steering column 70 having a toothedpinion 78. The pinion 78 is rotatable by the steering column 70 and thearrangement is such that when the driver of the vehicle turns thesteering column through some angle, the pinion moves the rack 80 acorresponding extent and the rack move ment is transmitted by theconnector 2 through the links 66 as a push to one steering arm and apull to the other. The limits of steering movement are determined by apair of adjustable stop screws 108 mounted transversely on the castings10 within the oval-section casing 94 and arranged to stop movement ofthe connector bracket 98 when the limit of turning has been attained.

In keeping with an important feature of the invention, the steeringmechanism and connections are arranged to insure that the road wheelsare not turned, or inadvertently steered, as the result of the wheel andaxles swinging vertically relative to the vehicle frame. For thispurpose, the tie link 66, which must swing up and down with the halfaxle 30 and the housing 30a, is so proportioned in length that it doesnot pull inwardly or push outwardly on the arm 64 (and thus does notturn the wheel about the steering axis 47a) as the wheel bounds andrebounds on encountering bumps or holes.

In achieving this advantageous result, the link 66 is made to swingabout its inner end through an arc approximately equal to any arctraversed by the axle 30 and housing 30:: in swinging vertically aboutthe horizontal pivot axis defined by the bolts 59 and the universalcoupling 26, 28. The outer end of the link 66 is made to move on aradius which is substantially equal to the radius on which the wheelmoves, so there is little or no movement of the arm 60 inwardly towardor outwardly away from the vehicle frame.

As shown best in Fig. 5, which is a diagrammatic view looking from thefront of the vehicle, the effective length of the link 66 between thecenters of the universal connections 100 and 64 at its inner and outerends, is made substantially equal to the distance between the innerpivot center 59a (defined by the bolts 59, Fig. 1) and the outer pivotcenter 36a (defined by the center of the universal connections 34 and36, through which the steering axis 47a passes). As the wheel 38 swingsvertically relative to the frame member 10 about the axis 59a, the link66 will correspondingly swing about its inner co'nnection 100. Butbecause the outer pivot centers 64 and 36 swing through substantiallyequal arcs of equal radii, the center 64 is not pulled inwardly towardthe frame relative to the center 36a. Therefore, the wheel is not turnedabout the steering axis as the wheel bounds and rebounds.

It will be noted that as illustrated in Fig. 5, the distance between thepivot points 100 and 64 is slightly less than the distance between thepivot centers 59a and 36a. This is simply to indicate that thesedistances need not be precisely equal in order to secure satisfactoryperformance. They need only be approximately equal to provide to apractical extent the advantage described.

In many instances it will be impractical to locate the pivot centers100, 64, 59a and 36a on the same vertical l e A li di a d n Fi the n e aP vot ,1!!! 6 t h in ad ent en s 9 the link 56. r a i bdgnt vo ice et 5a a 3 or t e sip linka e; Mo e ve due to p e m ta q s;,t el ni ew Pi t19.9. marh e t be Q Q I Yf W Y f the frame; 'so thatit is laterallydisplaced from the pivk center 5%: Under these circumstances, thedesired in munity to sp urious steering action as the, wheel bound andrebounds isi achieved by geometrically locating th four pivot points59a, 36a and 100, 64 so that they defin the corners of an approximateparallelogram. l?, show by dot-dash lines in Fig. 5. Since the sides P1and P of the parallelogram P are approximately equal in lengtl thedistances between the pivot centers 59a, 36a an 100, 64 areapproximately equal. As the suspensio: linkage formed by the half axle30 and the axle housin 30a swings vertically about the horizontal pivotaxis 590 the steering link 66 will swing about the pivot cente 100. Thepivot centers 36a and 64 will traverse arc of substantially equalangular extent and equal radii, 81 that the link 66 will not pullinwardly or push outwardl on the steering arm 60 (Fig. 1), and the wheelwill no be turned about its steering axis 47a.

I claim as my invention.

1. In a vehicle having a frame and a power uni mounted forwardlythereon, the combination comprising a live half axle and meansuniversally connecting its inne end to be driven from said power unit, ahousing for sait axle and first pivot means connecting said housing toth frame to swing vertically about a horizontal axis passin through theeifective center of said universally connectint means, a stub axleuniversally connected to the cute .end of said half axle, a universalball joint having a firs part fixed to the outer end of said housing anda secont part journaling said stub axle, a steering mechanism in cludinga rack mounted on the frame forwardly of th power unit, a steeringcolumn located outwardly fron the horizontal axis of said first pivotmeans, a pinion 01 said column meshed with said rack, a connector I0(rigidly fixed to said rack and movable transversely of tht vehicletherewith, a link universally pivoted at its one em to said rod, saidlast pivot connection being located in wardly from said steering column,means universall pivoting the other end of said link to said second baljoint part, the centers of said universal pivots at the end of said linkand the centers of said first pivot means ant said ball joint beinglocated substantially at the corners o a parallelogram, as viewed fromthe front of the vehicle so that the stub axle is not turned relative tothe half 3X11 as a result of the latter swinging vertically relative toth frame.

2. In a vehicle having a frame including a pair 0 spaced,longitudinally-extending side frame members ant a power unit mountedforwardly on said frame, the com bination comprising a live half axleand means universall: connecting its inner end to be driven from saidpowe unit, a housing for said axle and first pivot means con nectingsaid housing to the frame to swing vertically abou a horizontal axispassing through the effective center 0 said universal connecting means,a stub axle universallj connected to the outer end of said half axle, auniversa ball joint having a first part fixed to the outer end 0 saidhousing and a second part journaling said stub axle, steering mechanismincluding a rack mounted on 11111 frame forwardly of the power unit, asteering column lo cated outwardly from the horizontal axis of said firspivot means, a pinion on said column meshing with sair rack, a connectorrod rigidly fixed to said rack and mov able transversely of the vehicletherewith, a tubular cros: brace enclo'sing said connector rod andinterconnecting said spaced, longitudinally-extending side frame membersa link universally pivoted at its one end to said rod, sait last pivotconnection being located inwardly from sair steering column, meansuniversally pivoting the other em of said link to said second ball jointpart, the centers 01 7 aid universal pivots in the ends of said link andthe enters of said first pivot means and said ball joint being Jcatedsubstantially at the corners of a parallelogram as iewed from the frontof the vehicle, so that the stub axle not turned relative to the halfaxle as a result of the 5 atter swinging vertically relative to theframe.

References Cited in the file of this patent UNITED STATES PATENTS894,060 Ruemelin July 21, 1908 10 Kennedy Apr. 15, 1913 Brown Nov. 10,1914 Wagner May 5, 1936 Paton Mar. 30, 1937 FOREIGN PATENTS France Dec.17, 1923 Great Britain Mar. 19, 1934 Great Britain Jan. 27, 1941 GreatBritain Mar. 11, 1949

